Application user interfaces can be initially designed to support different display screen sizes or a single display screen size. User interfaces designed to run on different screens sizes are specified in a normalized form, independent of size. For example, design can be specified in terms of percentages, such as a button coded to be twenty percent from the left. Subsequently, the normalized form can be projected to different screen sizes. Application user interfaces designed to run on a particular display screen are written solely for that display screen. More specifically, the user interface can be hardcoded for the target screen. For example, a button can be specified statically in terms of screen pixels.